1. Field of the Invention
The present invention relates to an electronic device with multiple bonding wires, a method of fabricating such a device and a method of testing device bonding wire integrity.
2. Discussion of the Related Art
As is known, electronic power devices frequently require the use of two or more bonding wires between the pin of the device package and the die in which the device is formed when low resistivity is required and/or when the bonding wires are called upon to withstand strong current.
In the case of multiple-wire connections, a problem of checking the integrity of all the wires at the final testing stage arises. To solve this problem, the prior art has proposed splitting the contact pad to which one end of each of the bonding wires is bonded, as well as the component connected to the pad, and connecting each bonding wire to a respective portion of the split pad. Each wire is separately tested by separately turning on each component connected to it.
The above solution is shown schematically in FIGS. 1 and 2. FIG. 1 shows an electronic device 1 comprising an output stage component (here, a MOS transistor 2), one terminal of which is connected to a contact pad 3 in turn connected to a pin 4 by two wires 5. FIG. 2 shows the same device--indicated at 10--modified according to the above known solution. In this solution, component 2 is split into components 2a and 2b. The output terminals 6a and 6b are connected to respective pads 3a and 3b from which pad 3 was split. Components 2a and 2b include separate control terminals 7a and 7b for operating them independently. Pin 4 is connected by one wire 5 to pad 3a, and by the other wire 5 to pad 3b.
By turning components 2a and 2b on independently and determining if they conduct, the above solution therefore enables one to determine separately whether either wire 5 is faulty.
This solution, however, inevitably complicates the drive stage (not shown) of the device, which must be capable of turning on each component 2a and 2b separately. An additional control stage is also required for enabling the testing function of each component and selecting which output stage is to be activated. Moreover, splitting the output component and its respective pad, the need for electrically isolating the split components, and the presence of additional components for performing the test functions, considerably increase the area of the electronic device.
This drawback is further compounded when, instead of splitting a single output component, a bridge configuration is used as the output component requiring splitting of all four bridge elements.
It is an object of the present invention to provide an electronic device, a fabrication method, and a test method designed to overcome the drawbacks typically associated with the above known solutions, while at the same time ensuring reliable testing of the bonding wire integrity.